Apparatus for and method of wrapping



NOV. 21, 1961 c J R H ET AL 3,009,298

APPARATUS FOR AND METHOD OF WRAPPING Filed June 2, 1958 3 Sheets-Sheet 1 1 14 L 66 18 34 i I 9148 64" F'IE 1 F'Il3 2 INVENTORS CARL J. GERLACH ROBERT G. BUSH ATTORNEY Nov. 21, 1961 c. J. GERLACH ET AL 3,009,298

APPARATUS FOR AND METHOD OF. WRAPPING 3 Sheets-Sheet 2 Filed June 2, 1958 mm M m-HIHHII m mm um wk o on Om \OO B m9 w mm E B mm ATTORNEY MN. m E. m

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APPARATUS FOR AND METHOD OF WRAPPING 3 Sheets-Sheet 3 Filed June 2, 1958 F-IE E INVENTORS CARL J. GERLACH ROBERT e. ausn BY MW ATTORNEY Unite States ware Filed June 2, 1958, Ser. No. 739,376 14 Claims. (Cl. 53-22) This invention appertains to wrapping machinery and methods and relates more particularly to machines for automatically enclosing and sealing articles within a wrapper of impervious sheet material in a continuing, high speed operation.

It is a common practice in the packaging industry to seal perishable articles, and more particularly food products such as cheese, sliced meats and the like, within a wrapping of impervious sheet material and to exhaust from the packages thus formed most of the air entrapped within the packages with the wrapped articles. Such practice possesses numerous advantages which are well recognized in the industry. However, partial or complete evacuation of air from such packages as heretofore practiced is not entirely beneficial from the standpoint of preservation of a perishable commodity because it tends to draw moisture therefrom, frequently to an extent impairing the quality thereof by noticeably altering its flavor, texture and appearance. Such withdrawal of moisture from a wrapped article of food is particularly objectionable when the wrapping material is transparent because some of the withdrawn moisture usually collects as an oily appearing film on the surface of the article as well as on the inner surface of the wrapper, thereby impairing the saleability of the package.

it is an object of the present invention to provide an improved method of wrapping articles.

Another object is to provide an improved method of wrapping perishable articles, particularly items of food.

Another object of the invention is to provide a method of packaging articles which displaces the air entrapped within the package and substitutes therefor an inert gas.

Another object is to provide a method of purging air from packages by displacing the air by an inert gas, which is particularly adapted for use in conjunction with automatic packaging machines of the type wherein a succession of continuously advancing articles are entubed within a continuous tube of wrapping material which is flattened and sealed at suitable intervals to enclose the desired number of articles within each of the tube sections, i.e., the individual packages thus formed.

Another object is to provide a method of packaging articles whereby an inert gas is used to displace the air entrapped within a tube of wrapping material containing the articles, so as to precondition the tube for subsequent sectionalizing and scaling in a manner enclosing a predetermined number (usually one) of the articles in each section surrounded by an atmosphere of gas inert to both the article and the wrapping material.

Another object is to carry out the above described method in a manner that avoids subjecting the articles to reduced pressure and thus minimizes any tendency to withdraw moisture from the wrapped articles as a consequence of a pressure differential interiorly and exteriorly of the article.

Another object is to provide a packaging method whereby air is purged from within a tube of packaging material by a flow of an inert gas within the tube prior to completion of each package by flattening and sealing the tube.

Another object of the invention is to provide a method of manufacturing, filling, and gassing flexible, sealed packages containing articles apt to deteriorate in an atatent O i 3,009,298 Patented Nov. 21, 1961 mosphere of air, whereby all or substantially all of the air that otherwise would be entrapped within the packages is replaced by an inert gas as an incident to the process of forming and filling the packages.

Another object is to provide an apparatus for performing the method of the present invention.

Other objects and advantages of the invention will become apparent from the following description and accompanying drawings, in which:

FIG. 1 is a perspective of a wrapping machine with the air purging apparatus of the invention operatively incorporated therewith.

FIG. 2 is an enlarged fragmentary plan showing parts of the wrapping machine and the air purging apparatus of FIG. 1.

FIG. 3 is a schematic perspective of parts of the wrapping machine and the air purging apparatus of FIG. 1.

FIG. 4 is a schematic view partly in side elevation and partly in longitudinal section of part of the wrapping machine of FIG. 1 and showing the relationship thereto of the air purging apparatus of the invention.

FIG. 5 is an enlarged section along lines 5-5 of FIG. 4.

FIG. 6 is an enlarged section along lines 66 of FIG. 2.

FIG. 7 is a schematic perspective similar to FIG. 3 but showing a slightly modified form of the air purging apparatus of the invention.

The air purging apparatus 10 of the present invention is illustrated in FIGS. 1-6 as being cooperatively associated with an automatic wrapping machine 12 so as to displace with an inert gas the air that otherwise would be entrapped in each package formed by the wrapping machine 12. Without limitation as to the type of wrapping machine whose end product is improved by the method and apparatus of the present invention, the wrapping machine 12 chosen for illustration in cooperative association with the air displacing apparatus 10 is of the type disclosed in Patent No. 2,602,276, issued July 8, 1952 to Campbell, to which reference can be had for a complete description of its construction and manner of operation. It will suffice, therefore, for the purposes of the present disclosure to explain that in the wrapping machine 12 a web 14 of sheet stock wrapping material supplied from a reel 16 is shaped by a tube forming device 18 to entube a series of spaced articles 20 which are delivered in a continuing operation to the wrapper 14 and the tube former 18 by an infeed conveyor 22 (FIG. 4).

The tube former 18 is of inverted channel form, thus presenting a passage 23 in its under surface and extending longitudinally thereof. The infeed conveyor 22 propels the articles 20 successively into the inlet end of the passage 23, while the top and two lateral sides of the passages 23 are lined by the advancing web'14 of wrapping material. The web 14 and the articles 20 continue to advance at identical speeds, and during their progress through the passage 23 theweb 14- of wrapping material is so folded around the articles 20 that the side margins 24 and 26 of the wrapper web 14 are disposed in overlapping relation beneath the articles 20, as more fully explained in the hereinbefore mentioned Patent No. 2,602,276, and as shown in FIG. 5. Moreover, the wrapping machine 12 includes a sealing device (not shown) within the former 18 for longitudinally sealing the tube 28 into which the wrapper web 14 is formed by the forming device 18. Said sealing device operates by welding the overlapping marginal portions 24 and 26 together, thus effectively entubing the articles 20 in spaced apart relation within the tube 28, as best shown in FIG. 5.

Upon leaving the former 18, the tubed wrapper 28 and the articles 20 therewithin pass along a supporting table 30, the upper surface of which is provided with a plurality of laterally spaced longitudinally extending grooves 32 (FIGS. 3-6). During such advance along the supporting table 30, the tube 28 and the articles therewithin are subjected to the lateral confining pressure of horizontally opposed conveyor belts 34 and 34a (FIGS. 1-6) extending along opposite sides of the supporting table 30. Each of these belts is trained around forward and after pulleys 36 and 36a, respectively, carried by vertical shafts 38 and 38a, respectively, one of which is power driven by any suitable means (not shown), while the other is preferably an idler shaft. The inner run of each belt 34, 34a has a pressure plate 40, 40a operatively associated therewith. Each pressure plate is carried by a plurality of horizontal rods 42, each of which extends slidably through a lug 44 rigid with the supporting table 30 between the two runs of the associated belt. Coil springs 46, under compression between the pressure plate 40, 40a and the lugs 44, constantly urge the inner run of the associated belt 34, 34a laterally inward thereby pressing said inner run into sufiicient pressure engagement with the tube 28 to enable the belts 34, 34a to effect advancement of the tube 28 with the articles 20 therein.

The belts 34, 34a terminate just short of a pair of vertically opposed rollers 48 and 49, respectively, between which the tube 28 passes. These rollers 48 and 49 flatten the tube 28 by pressing the upper and lower sides of the tube 28 together as clearly shown in FIG. 4. Such flattening occurs between each two adjacent articles 20 as the tube with the articles therein passes beyond the discharge end of the supporting table 30. Moreover, the rollers 48 and 49 are provided with sealing means (not shown) and severing means (not shown), as more clearly explained in the aforesaid Patent No. 2,602,276, so that each article is sealed individually within a package whose wrapping consists of a suitable length of the web 14 of wrapping material.

While the present invention is not directly concerned with the particular type of material constituting the web 14 or with the manner in which the packages are sealed, it should be noted that the adhesion required for both the longitudinal sealing and the transverse sealing of the web 14 can be brought about either by means of a suitable adhesive or, if the web 14 is formed of a substance amenable thereto, by a heat sealing operation, both of said heat sealing and adhesive sealing operations being well known in the art.

The apparatus for displacing the air that otherwise would be entrapped in each package along with the article 20 therewithin, includes an elongate tube 60 of quite small cross sectional size and preferably of sufficient rigidity to sustain its own weight without undue fiexure although supported at but one end. In practical operation, standard stainless steel tubing of A; inch outside diameter has proven to be satisfactory. The tube 60 is affixed at one end to, and is supported by, a manifold block 62 that is rigidly supported adjacent the inlet end of the tube former 18 by a transverse bracket 64 (FIG. 1) that extends rigidly between frame members 66 of the wrapping machine 12. From the manifold block 62 the tube 60 extends through the passage 23 of the tube former 18 and beyond the same throughout only slightly less than the full length of the supporting table 30. Thus, a distributing head 68 on the unsupported end of the tube 60 is disposed adjacent the wrapper tube fiattening and transverse sealing rollers 48, 49, as best shown at FIG. 4. The distributing head 68 comprises a short length of tubing bent to substantially semi-circular form and secured to the end of the tube 60 substantially midway between the ends of the head 68 so that the two ends of the latter open rearwardly of the wrapping machine, i.e., the ends of the head 68 point in the direction opposite the direction in which the tube 28 and the articles 20 therewithin advance, as best shown in FIG. 2. Since the bore of the tube 60 communicates with that of the distributing head 68, gas flowing under pressure through the tube 66 will be jetted backwardly through the Wrapper tube 28, i.e., away from the sealing and severing rollers 48 and 49 and toward the tube former 18, where the wrapper tube 28 is open to the atmosphere.

The parts are so arranged that the part of the tube 60 that lies within the former 18 closely underlies the top wall of the passage 23, but not so tightly thereagainst that it interferes with movement of the web 14 between the tube 28 and the top wall of the passage. When the web 14 is threaded into the machine 12 its leading end is entered into the passage 23 between the tube 60 and the top wall of the passage 23, as clearly shown in FIG. 4, and when the articles 20 to be wrapped enter the former 18 they pass beneath the tube 60. Consequently, as the lateral edges of web 14 are folded downward and inward under the bottom surface of the articles 20, the wrapper tube 28 thus formed surrounds the tube 60 as well as the articles 20. However, as the wrapper tube 28 and the articles 20 therewithin advance along the supporting table 30, the tube 60 remains stationary so that as the wrapper tube 28 and the articles 20 approach the transverse sealing rollers 48 and 49, the wrapper tube 28 is drawn over and past the head 68 on the tube 60.

The manifold block 62 serves not only as the support for the tube 60, but likewise establishes fluid conducting communication between the tube 60 and a supply tube 70 which, as indicated in FIG. 4 leads from a pressure reducing valve 72 through a heat exchanger 74 and thence through a sheath 76 of heat insulating material to the manifold block 62. The heat exchanger 74 comprises a fluid-tight housing 78 through which circulation of any suitable heating medium, such as hot water, is maintained by inlet and outlet pipes 80 and 82, respectively, and within which the tube 70 is coiled, as indicated diagrammatically in FIG. 4. An inert gas, e.g., nitrogen, under suitable pressure is supplied to the pressure reducing valve 72 from any suitable source such as a conventional compressed gas bottle 84.

From the above description of the constituent parts of the gas supply system of the invention and their arrangement with relation to the remainder of the wrapping machine 12, it will be understood that nitrogen, or another suitable inert gas, is supplied to the interior of the tube 28 of wrapping material continuously as the tube 28 and the articles therewithin advance through the former 18 and along the supporting table 30. Since the distributing head 68 of the tube 60 is disposed adjacent the region where the wrapper tube 28 is transversely sealed, gas thus supplied to the interior of the wrapper tube creates an increase of pressure within the same at a substantial distance from the open end thereof where the tube 28 is being formed. Although this increase in pressure is slight it does create a sufficient pressure differential between the inside and the outside of the wrapper tube 28 to induce a backward flow of the gas through the wrapper tube 28 toward the open end thereof. In thus flowing backward through the wrapper tube 28, the inert gas flushes, or purges, the air that is entrapped within the wrapper tube 28 as the latter is formed within the forming device 18, where the purged air and any excess of the inert gas escapes to the atmosphere through the open end of the wrapper tube 28. Consequently, each article 20, when finally sealed within its individual package after passage between the sealing and severing rollers 48 and 49, is surrounded by an atmosphere of nitrogen, or whatever other inert gas is employed in practicing the invention.

In order to increase the efiiciency with which the inert gas purges air from within the wrapper tube 28, means are provided for causing the backwardly flowing gas to pass alternately to opposite sides of each article 20 within the tube 28. This means for causing alternation of flow comprises two idler rollers 90 and 91, respectively, each of which is freely rotatable on a shaft 92 extending between a pair of upstanding brackets 94. All four of these brackets 94 are rigid with the supporting table 30, as best shown in FIG. 3.

The rollers 90 and 91 are disposed at a height above the supporting table 30 substantially corresponding to the vertical dimension of the articles 20 to be wrapped, so that as an article 20 passes beneath either roller 90 or 91, the upper surface of the tube 28 of wrapping material is pressed against the top of the article, or at least into such' close proximity thereto, that substantial restriction is presented to the flow of gas between the article and the upper wall of the wrapper tube '28. Therefore, the backwardly flowing gas within the tube 28 is forced to flow under the article 20 throughout both times that the upper wall of the tube 28 is pressed against or toward the upper surface of the article. i

It is to accommodate the backwardly flowing gas during this phase of the wrapping operation that the grooves 32 are provided in the upper surface of the supporting table 30. These grooves 32 permit longitudinally extending sections 100 of the lower wall of the wrapper tube 28 to be flexed downward away from the under surface of the associated article 20, and thereby to provide passages 102 between the bottom surface of the article 20 and the bottom wall of the wrapper tube 28, through which passages the backwardly flowing gas can escape past the article while the same is in cooperative association with either the roller 90 or 9-1. The rollers 90 and 91 are spaced apart a distance substantially corresponding to the length of one of the articles 20 as clearly shown in FIG. 4, and in order to enable the rollers 96 and 91 to press the top wall of the wrapper tube 28 against or close to the tops of the articles 20, each roller 90, 91 is provided with a circumferential groove 96 within which the inert gas tube 60 is accommodated in the region thereof where it extends past the roller. Each groove 96 is of considerably greater cross sectional area than the tube 60, so as to prevent binding between the stationary .tube 60 and the moving wrapper tube 28.

In order to insure that the backwardly flowing gas passes above each article 20 at least once during the time that the article is exposed to the backward flow of purging gas, the longitudinal grooves 32 are obstructed by blocks 104, one of which is fitted into each groove 32 at apoint between the locations of the two rollers 90 and 91.

Thus it may be seen that as the wrapper tube 28 with articles 20 entubed therein in spaced apart relation prothrough the wrapper tube 28, and around the articles 20 therewithin. and disposed to the rear of the distributing head 68. While thus flowing through the Wrapper tube 28, the inert gas purges the tube 28 of air, this purging operation being made more thorough and effective by the alternation of flow of the inert gas to opposite sides of the articles 20 by the rollers 90 and 91 and the blocks 104, as hereinabove described.

The purpose of passing the inert gas through the heat exchanger 74 is to prevent the inert gas from being delivered into the tube 28 at a temperature significantly below that of the ambient atmosphere, and thus to avoid the excessive swelling of individually sealed packages whichwould result from the expansion of an excessively cold gas within the sealed packages'after the same have been dischargedfrorn the wrapping machine. Undercertain circumstances, in fact, it is desirable that the inert gas be delivered into the wrapper tube 28 at'a temperature considerably higher than that of the ambient atmosphere, so that subsequently and after each individual package has been sealed at both ends, the gas will cool and thus contract to an extent at least tending to draw the wrapper tightly against the wrapped article. This causes the ultimate package to conform closely to the shape and size of the wrapped article there-within.

FIG. 7 illustrates a slightly modified form 10a of apparatus for performing the method of the present invention. The apparatus 10a differs from the apparatus here inabove described only in that instead of employing a single gas delivering tube, it includes a plurality of parallel tubes 60a, all of which are supported by and project from a common manifold block 62a, whereby the inert gas is delivered equally to the several tubes 60a from a supply tube 70a in the same manner as the manifold block 62 operates in the previously described form of the invention. Under certain circumstances of operation, a plurality of tubes 60a is found to be advantageous over a single tube, not only because of an increased flow of gas that is thereby made possible, but also because of the more even distribution of gas transversely of the tube 28 which contributes to the efiiciency with which air is purged from the tube 28 of wrapping material.

In the form of the invention illustrated in FIG. 7, the rollers a and 91a are each provided with a number of relatively large grooves 96a corresponding to the number of tubes 60a so that the rollers 90a and 91a can press the upper surface of the tube 28 of wrapping material against or closely toward the upper surface of the articles 20 without unduly squeezing the top wall of the. tube 28 and thereby interfering with the movement of the tube 28 along the tube 60a.

While two particular forms of apparatus for performing the method of the present invention have been shown and described, it will be understood that the apparatus is capable of further modification and variation without departing from the principles of the invention and that the scope of the invention should be limited only by the scope and proper interpretation of the claims appended hereto.

The invention having thus been described, what is believed to be new and desired to be protected by Letters Patent is:

1. Packaging apparatus comprising means for advancing a tube of wrapping material having entubed therein an article to be wrapped, means for transversely flattening said tube in advance of said article, means for introducing a gas into said tube in advance of the article therein to induce a backward flow of said gas through the tube past the article, and means for directing said backward flow alternately to opposite sides of the article.

2. Packaging apparatus comprising means for advancing a tube of wrappingmaterial having entubed therein articles to be wrapped, means for transversely flattening said tube in advance of said articles, means for introducing a gas into said tube in advance of the articles therein to induce a backward flow of said gas through the tube past the articles, and means engaging opposite sides of the tube at different distances from said flattening means to press said sides of the tube into flow restricting relation with opposite sides of each article at different distances from said flattening means to direct said backward flow alternately to opposite sides of thearticle.

3. Wrapping apparatus comprising means for entubing articles within a tube of wrapping material, means for transversely sealing said tube in advance of the articles, means for introducing a gas into said tube in advance of a plurality of the articles within the tube to purge the tube of air by a backward flow of said gas'within the tube past said plurality of articles, and means for directing said backward flow alternately to opposite sides of each of said articles. I p s 4. The method of wrapping articles individually which includes continuously advancing a tube of wrapping material having articles to be wrapped entubed therewithin and spaced apart longitudinally of the tube, transversely sealing said tube between the leading article and the others of said articles, injecting an inert gas into the transversely sealed tube in advance of said other articles to induce a backward flow of the gas within the tube, and directing said backward flow of the gas alternately to opposite sides of said other articles.

5. The method of Wrapping articles individually which includes continuously advancing a tube of wrapping material having articles to be Wrapped entubed therewithin and spaced apart longitudinally of the tube, transversely sealing said tube between the leading article and the others of said articles, injecting a heated inert gas into the transversely sealed tube in advance of said other articles to induce a backward flow of the gas within the tube, and directing said backward flow of the gas alternately to opposite sides of said other articles.

6. Packaging apparatus comprising means for advancing a tube of Wrapping material saving entubed therein an article to be wrapped, means for introducing a gas into said tube in advance of the article therein, means carried by said gas introducing means for jetting the gas backward through said tube past the article, and means for directing said backward flow alternately to opposite sides of the article.

7. Packaging apparatus comprising means for entubing articles Within a tube of wrapping material, means for introducing a gas into said tube in advance of a plurality of the articles Within the tube, a gas distributing means carried by said gas introducing means for jetting the gas backwardly through said tube past said plurality of articles to purge the tube of air by a backward flow of said gas within the tube, and means for directing said backward jetted flow alternately to opposite sides of each of said articles.

8. Packaging apparatus comprising means for advancing a tube of wrapping material having entubed therein an article to be wrapped, means for transversely flattening said tube in advance of said articles, means for introducing a gas into said tube in advance of the articles therein, a gas distributing head carried by said gas introducing means for jetting the gas backwardly through said tube past the article, and means engaging opposite sides of the tube at different distances from said flattening means to press said sides of the tube into flow restricting relation with opposoite sides of the article to direct said backward flow alternately across opposite sides of the article.

9. In a packaging machine including means for advancing in a given direction a tube of wrapping material having entubed therein an article to be Wrapped and means for transversely flattening said tube in advance of said article; an apparatus for purging the air entrapped in said tube, comprising means for introducing a gas into said tube in the path of said article to induce a backward flow of said gas through the tube in a direction opposite to said given direction of wrapping material advance and past the article, a supporting table disposed in the path of siad article and upon which said tube rides as it advances, said table having at least one longitudinal groove therein opening through the top thereof, means carried by said table to subject said tube to lateral pressure as it advances over said tab-1e, other means carried by said table and disposed thereabove at a height corresponding to the vertical dimension of the entubed article and pressing said tube against the top of said article to present a substantial restriction to the flow of gas over the top of said article and forcing a portion of said tube into said groove to provide a passage for the backward flow of gas beneath said article.

10. In a packaging machine including means for advancing in a given direction a tube of wrapping material having entubed therein an article to be wrapped and means for transversely flattening said tube in advance of said article; an apparatus for purging air entrapped in said tube, comprising means for introducing a gas into said tube in the path of advance of said article to induce a backward flow of said gas through the tube in a direction opposite to said given direction of wrapping material advance and past the article, a supporting table disposed in the path of said article and over which said tube rides as it advances, said table having at least one longitudinal groove therein opening through the top thereof, means carried by said table engaging the side and top of said tube to subject the tube to lateral and downward pressures so that a lower portion of said tube is forced into said groove whereby a substantial restriction to said flow of the gas is affected across the top of said entubed article and a passage is provided through said lower tube portion for the flow of the gas beneath said article.

11. The apparatus for purging entrapped air in an advancing tube of wrapping material as set forth in claim 10 and wherein said means carried by said table comprises a pair of upstanding pressure plates disposed along opposite longitudinal edges of the table and engaging the adjacent sides of said tube, means for pressing said plates inwardly of said table to apply a lateral pressure against said adjacent sides of said tube and press said adjacent sides against the entubed article, and a pair of longitudinally spaced rollers carried by said table to ride upon the top of said tube to apply pressure to the top of the tube and press the tube against the top of the entubed article so that said pressures force the lower portion of said tube to distend into said groove.

12. The method of wrapping articles individually which includes advancing a tube of wrapping material having longitudinally spaced articles to be wrapped entubed therein and each of said articles occupying substantially the entire cross sectional area of said tube, transversely sealing said tube between each two adjacent articles, injecting a gas into the transversely sealed tube in advance of said article to induce a backward flow of the gas within the tube, restricting the rearward flow of the gas above the entubed article at a location along the path of backward flow of the gas, and forming a pass ge in the bottom of said tube at said location for the flow of the gas beneath the article at said location whereby the gas will flow alternately across the top and the bottom of said article.

13. The method of wrapping articles individually which includes advancing a tube of Wrapping material having longitudinally spaced articles to be wrapped entubed therein and each of said articles occupying substantially the entire cross sectional area of said tube, introducing a gas into said tube in advance of said articles, jetting the gas backwardly through said tube, restricting the rearward jetted flow of gas above one of said articles at a location within said tube in advance of the other articles entubed therein, and forming a passage in said tube beneath said one article at said location to permit the backward jetted flow of gas therethrough and whereby the jet flow will be directed alternately across the top and the bottom of said one article.

14. Packaging apparatus comprising means for entubing an article within a tube of wrapping material, means for introducing a gas into said tube for purging the tube of air by a flow of said gas past the article, and means operable to direct the flow of said gas across first one side of the article and then another.

References Cited in the file of this patent UNITED STATES PATENTS ,367 Maxfield May 30, 1939 2,919,990 Podlesak et al. Jan. 5, 1960 FOREIGN PATENTS 7.9 .425 Great Britain Mar. 5, 1958 

